Microorganism strains with enhanced producibility can be developed via discovery and appropriate utilization of genetic factors, which are directly/indirectly involved in the early stages of glycolysis, for the preparation of strains producing useful products such as amino acids on a large scale. Representative examples of the technologies to be used for this purpose may include global transcription machinery engineering (gTME), which is an approach to regulate the expression of all of the genes in a cell by inducing random mutagenesis to the recruiting proteins of RNA polymerase. For instance, a research group in the Massachusetts Institute of Technology has shown success in significantly enhancing tyrosine producibility in E. coli using the gTME technology (U.S. Pat. No. 8,735,132).
The RNA polymerase used in the transcription step in microorganisms is a macromolecule consisting of 5 small subunits, i.e., two α factors, one β factor, one β′ factor, and one co factor, and its holoenzyme is indicated by α2ββ′ω. Sigma (σ) factors, together with the holoenzyme, are essential factors for the initiation step of transcription, which provides a promoter-binding specificity of RNA polymerase. A Corynebacterium strain has 7 kinds of sigma factors (SigA, SigB, SigC, SigD, SigE, SigH, and SigM) which regulate the transcription of particular gene groups according to the changes in external environment (Journal of Biotechnology 154. 2011. 101-113). In particular, SigA is a major regulator among the sigma factors involved in the regulation of most housekeeping genes and core genes. According to the previous study reports, attempts were made to improve the producibility of target materials by random mutagenesis of SigA (Metabolic Engineering 9. 2007. 258-267) and there was also a report regarding the study of increasing L-lysine producibility using a Corynebacterium strain (International Publication No. WO 2003-054179).